Artificial interchangeable tooth



A. SCHWARTZ AND J. WIEDER.

ARTIFICIAL INTERCHANGEABLE TOOTH.

APPLICATION F|LE D DEC. 7, I920.

1,426,1 14. Patent-ed'Aug. 15, 1922.

war

"UNITED STATES PATENT OFFICE.

ABRAHAM CHWARTZ AND JOHN WIEDER, OF BOSTON, MASSACHUSETTS.

ARTIFICIAL INTERGHANGEABLE TOOTH.

Specification of Letters Patent. Patented A 15, 1922.

Application filed December 7, 1920. Serial No. 428,887.

changeable teeth, and more particularly to crowmis quickly and easilydetachable asa type thereof wherein a metallic back is permanently fixedto lateral anchorages such as afforded by natural teeth, and with afacing or crown of porcelain or the like constituting the body of thetooth applied'to said metal back in a manner so as to be detachable andinterchangeable when required, but with interlocking provision betweenthe metal back and the porcelain crown so constructed as to withstandpressures exerted upon it in alldirections on the occlusion of opposingteeth. A principal ob- .ject of the invention is to provide meanswhereby the porcelain "crown anchored.

and secured to the metallic backing or base more strongly and securelythan has heretofore been possible while at the same time the requiredfor replacement on account of breakage or for other reasons. A furtherobject is to provide an interfitting engagement between the metal backand' the porcelain crown affording an absolutely firm base for the crownwhereby any possibility of the crown being crowded back beyond itsnormal position is prevented and additional strength and support for theporcelain ob tained. In accordance with our invention the cusp andbiting surfaces of the tooth are of porcelain instead of metal as iscommonly the case with teeth of the present interchangeable type. Tothese ends we provide a metal base or back of a boxed form affordingmaximum strength and rigidity,

and having undercut angles or edges with which the porcelain crown hasinterlocking engagement substantially throughout the extent thereof. Afurther object is to provide an improved mounting of the porcelain crownupon its metallic base which permits any necessary grinding away of thelnner end of the tooth thus constituted for fitting it in place withoutweakening or interfering with the interlocking engagement between theporcelain and the metal base. The foregoing and other objects andadvantages of the invention will more fully appear from the followingdetailed description, and the distinctiw features of novelty will bepointed out in the appended claims.

Referring to the drawings;

Figure 1 is a side elevation showingthe I porcelain crown of ourinvention removed;

Figure 2 is a front view thereof; Figure 3 is an end view looking fromthe outer. end of the crown; I

Figure 4 is a side view of the metallic base removed;

Figure 5 is a front view thereof;

Figure 6 is an'end view looking from the I inner end thereof;

Figure 7 is'a side view of the porcelain I crown assembled with themetallic base, i. e. the complete tooth;

F gure 8 is a front view thereof; Figure 9 1s a transverse vertlcal.section; and I Figure 10 is a horizontal section on line 10 10 of Fig.7.

l0 indicates the porcelain crown of the.

invention, the cus portion thereof-being indicated at 10*. his crown isrecessedfat its upper portion on its inner side toreceive the metallicbacking. In accordance with our invention this recess is approximatelyL-shaped in transverse section, with the corner angle so thereofhowever, somewhat acute for a purpose that will be ex- I plained. Thecrown is rebated at its sides around this recess as indicated at 11 withthe rebated edges undercut as indicated at 12. The base ledge orshoulder of this recess is al so rebated around the edge thereof asindicated at 13, this rebate sloping'downward or toward the cusp 10 ofthe crown as it'extends toward the outer side thereof as indicated at13*, this slope corresponding generally to the slope indicated at 14, ofthe base of the crown recess which forms the longitudinal median bore 15from the inner end thereof, to receive the metallic'pin of the base,this bore opening into the recess at the back of the crown as; indicatedat v acute angle 00. The crown is formed with a 15, and extendingdownward 'or outward of the tooth well toward the end of the cusp asindicated at 15*.

The fixed metallic backing or base for interfitting and interlockingwith the "interchangeable crown facing described, comprises an L-shapedplate or web member 16 bearing at its inner-side apin .17, which 'fitsinto the hole 15. This plate or web-bears at its sides, :flange or cheekportions 18, which extend inwardly and are adapted to fit closely intothe undercut rebates 11, at the sides of the crown recess. This metallicbacking has its bottom sloped downwardly inward as indicated at 19 tofit thesloping bottom 14, ofthecrown recess'and its curving outer sideportion bears a downwardly extendin rim or shroud QO fitting the rebatel3 0 the crown,.the side-portions thereof also sloping downwardlyinwardas indicated at 20 to fit'the slopingcontour 13 at the sides ofthe rebate 13.v With this construction it will be noted that themetallic back is of a boxed form that is stiffened and braced by itsseveral parts in all directions so as to afiord greatest possiblestrength for a given amount of metal. By reason of-the extendedinterlocking areas of the porcelain with the metal back the porcelaincrown is more firmly held and is less apt tobreak than inany previous.form of artificial interchangeable tooth known to us. The bottom of theback provides a ledge of substantial extent constituting a firm andreliable abutment for the crown preventing any possible chance of thecrown being crowded back beyond its normal position as has been :thecase with previous types of interchangeable crowns. Itwill also be notedthat we :provide strongandreliable .means for interlocking the metallicback with the porcelain facing aroundthe periphery, as well as atthelongitudinal median line of the tooth, this being accomplished by theinturned flanges 18 engaging undercut lateral rebates 11, while thedownward slope of the bottom 14, provides an interlocking abutment withthe bottom 19 and rim shroud 20 of the metal back further holding thecrown facing 10 secure against pulling off from the back, all theseinterlocking points of engagement being additional and supplementary tothe hold obtained. by the pin 17 in the'bore 150f the facing. Thus it isonly necessary'to cement or otherwise secure'the porcelain facing to themetal back sufiici ently to prevent displacement of the facing, alltendency to 'may be filled with metal 22 to complete the contour of thetooth and reinforce and stiffen "the '-back. 'This metal back may 'be"formed as usual of gold'or suitable composition'wlhich needn'otbedetailed herein. It

:will be understood that the metal back describedmay be secured tosuitable lateral anchorages in uSuaLmanner, indicated at 123.

WV e are aware ithatathe invention may be embodied inother specificforms without de- Qparting from the spirit :Or essential attributesthereof, and we therefore desire the present embodiment :tobe consideredin all '1. An artificial tooth comprising a de- .tachable v.andinterchangeable porcelain or :like facing-rand a :metalback of boxedform,

said facing having arecess whichs'aid back'is fitted, said s'facingand,said backhaving peripheral portions interlocked ttO pre- 1 ventlateraldisplacementof said facing, and said back presenting a base ofsubstantial dimensionengaginga ledge of said facing.

An .iarti ficial "tooth comprising a deitachable and interchangeableporcelain .or

like facing recessed at the upper portion of the inner-side thereof withundercut rebates around the .side's of said recess, and a metal back ofboxed form Tbearing rim portions having'an interlocking fit with; saidfacing,

and said back presenting a base ofsubstan- 'tialdimension engaging aledge ofsaid facing.

rebates around the-sides of said recess,and-a metal back'bearing rimPOI'UOIIS having an 3. An artificial tooth ,compr'isinga porcellainorlike facingrecessed atcthe upper-portion of the Tinnerside thereofwith. undercut interl'ocking fit with said :facing :andfsaid backbearingqa'lso a pin engaging a longitudinal 'medi an hole-ofsaid facing.

4. An artificial tooth comprising a porcelain or like faclng with arecessln its Inner 'upper'port-ion formingan acute angle at itsbottomandca 'metaltback'fitted in said recess with itsbottomsloped tofit the-acute angle of said recess, said back bearing alsola pinengagingaklongitudinalmedian hole in said facing.

An artificial tooth comprising a porcelain or likefacing having "arecess in .its inner upper portion formlng an acutezangle at its bottomand with undercut rebates around .the sides-'of'said recess,andaimetalback fitted in said recess with .its bottom in-.terlocking"witht-he bottom thereofand with 'inturned cheeks projectingfrom the sides 'thereofzto engage said undercut rebates.

6. Anartific'ial tooth comprising a. porce-' lain or like facing havinga recess in its inner upper portion forming an acute angle at its bottomand with undercut rebates tudinal median hole of said facing whicharound the sides of said recess, and a metal hole opens into saidrecess. back fitted in said recess with its bottom in- In testimonywhereof, we have signed our 10 terlocking with the bottom thereof andwith names to this specification.

5 inturned cheeks projecting from the sides thereof to engage saidundercut rebates, said ABRAHAM SCHWARTZ. back bearing also a pinengaging in a longi- JOHN VVIEDER.

